Selective reflectivity process chamber with customized wavelength response and method

ABSTRACT

A customizable chamber spectral response is described which can be used at least to tailor chamber performance for wafer heating, wafer cooling, temperature measurement, and stray light. In one aspect, a system is described for processing a treatment object having a given emission spectrum at a treatment object temperature which causes the treatment object to produce a treatment object radiated energy. The chamber responds in a first way to the heating arrangement radiated energy and in a second way to the treatment object radiated energy that is incident thereon. The chamber may respond in the first way by reflecting the majority of the heat source radiated energy and in the second way by absorbing the majority of the treatment object radiated energy. Different portions of the chamber may be treated with selectively reflectivity based on design considerations to achieve objectives with respect to a particular chamber performance parameter.

This is a divisional application of prior application Ser. No.10/629,400 filed on Jul. 28, 2003 now U.S. Pat. No. 7,115,837 from whichpriority under 35 U.S.C. §120 is claimed; the disclosure of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of heat processinga treatment object such as, for example, a semiconductor substrate, and,more particularly to a process chamber having a selective reflectivityprofile for use in such heat processing.

Thermal processing of treatment objects such as, for example,semiconductor substrates, usually requires initially ramping thesubstrate temperature to a high temperature in a process chamber so thata process can be performed at that high temperature. In a so-called“soak” process, the substrate is left at a given process temperature fora specified period of time and is then ramped down in temperature forunloading from the process chamber.

Typical processes include annealing of ion-implantation damage, silicideformation, oxidation, film deposition and densification or reflow ofdeposited films. In some processes, it is desirable to minimize the timeat the high temperature. This can be achieved with what is generallyreferred to in the art as a “spike” or ultra-shallow junction (USJ)process, wherein the substrate is ramped up to a specified temperatureand then is immediately allowed to cool-down. This kind of process hasbeen found to be very useful for annealing ion-implantation damage thatis associated with an implanted dopant. That is, the heat treatmentserves to maximize electrical activation of the implanted species, asone objective, while minimizing dopant diffusion, as another objective.It is generally accepted in the prior art that these objectives comprisecompeting interests and that the spike anneal process appears to providethe best-known compromise with respect to optimizing both of thesecompeting objectives. As an example, ultra-shallow p-n junctions cam beformed through the combination of low-energy ion implantation with spikeanneals. The junctions have the desirable properties of shallow junctiondepths (typically <˜40 nm) as a result of the minimal time attemperature and low sheet resistances (typically <800 Ω/sq.) as a resultof the high temperature used to activate the dopants.

The characteristics of the spike process are sometimes described interms of the peak temperature and the width of the spike, oftenspecified by the time spent above a threshold temperature defined by(peak temperature −ΔT° C.), where ΔT is usually set as 50, 100 or 200°C. Sometimes the process is also characterized by a ramp-up rate and acool-down rate. It is evident that the ramping and cooling rates willtypically affect the peak width of the spike process. Successful spikeannealing, that gives the shallowest junctions with the lowest sheetresistances, often requires higher peak temperatures and narrower peakwidths. This is especially important for formation of junctions usingboron doping, where significant benefits can be gained through spikeanneals. A typical spike process can have a peak temperature of 1050° C.and a peak width of approximately 1.7 s for ΔT=50° C.

It is submitted that future device technologies will require furtherreductions in junction depth and sheet resistance and, hence, it isclear that improved RTP spike processes will be needed. The expectedtrend is that new processes will mandate a higher process temperaturethat is accompanied by a narrower peak width. The present inventiondescribes a highly advantageous approach in implementing such a newprocess, while providing still further advantages.

Temperature measurements in RTP systems, such as described above, arecritical with respect to process monitoring and control. When radiationpyrometers are used to measure, for example, wafer temperature, thewafer is observed by the pyrometer through an aperture in the processchamber wall. In some cases, it can be useful to make this chamber wallhighly reflecting at the pyrometer wavelength, because this conditiontends to increase the effective emissivity of the wafer at the pyrometerwavelength. This effect makes the emission of the wafer more closelyresemble that of a blackbody radiator. As a result, the pyrometerreadings are less sensitive to temperature measurement errors that arisefrom inadequate knowledge of the wafer's spectral emissivity at thepyrometer wavelength. This is a well-known principle for reducingtemperature measurement errors in pyrometry. Unfortunately,accommodating this emissivity characteristic, relating to pyrometry, mayadversely influence other important aspects of RTP system operation. Thepresent invention is considered to resolve this difficulty, as will bedescribed below, while providing still further advantages.

SUMMARY OF THE INVENTION

As will be discussed in more detail hereinafter, there is disclosedherein a system and associated method for processing a treatment objecthaving a given emission spectrum at a treatment object temperature so asto produce a treatment object radiated energy. The system includes aheating arrangement for heating the treatment object using a heat sourceradiated energy having a heat source emission spectrum at a heat sourceoperating temperature which heat source emission spectrum is differentfrom the given emission spectrum of the treatment object. Chamberdefining means is provided for use in exposing the treatment object to aportion of the heating arrangement radiated energy while supporting thetreatment object within a treatment chamber such that a first fractionof the heating arrangement radiated energy and a second fraction of thetreatment object radiated energy are incident on the chamber definingmeans bounding the treatment chamber. The chamber defining means isconfigured for responding in a first way to a majority of the firstfraction of the heating arrangement radiated energy that is incidentthereon and for responding in a second way to a majority of the secondfraction of the treatment object radiated energy that is incidentthereon. In one feature, the chamber defining means is configured torespond in the first way by reflecting the majority of the heat sourceradiated energy and to respond in the second way by absorbing themajority of the treatment object radiated energy.

In another aspect of the present invention, a system and associatedmethod are described for processing a treatment object. The systemoriginally includes an unmodified chamber arrangement for receiving andsupporting the treatment object during processing. The unmodifiedchamber arrangement provides a given maximum cooling rate of thetreatment object after being heated within the unmodified chamberarrangement, a modified chamber arrangement is used to replace theunmodified chamber arrangement. The modified chamber arrangementincludes chamber defining means for supporting the treatment objecttherein and is configured for providing a modified maximum cooling ratethat is greater than the given maximum cooling rate.

In still another aspect of the present invention, a system andassociated method are described for processing a treatment object havinga given emission spectrum at a treatment object temperature so as toproduce a treatment object radiated energy. The system includes aheating arrangement for heating the treatment object using a heat sourceradiated energy having a heat source emission spectrum at a heat sourceoperating temperature which heat source emission spectrum is differentfrom the given emission spectrum characteristic of the treatment object.Chamber defining means is used for exposing the treatment object to aportion of the heating arrangement radiated energy while supporting thetreatment object within a treatment chamber such that a first fractionof the heating arrangement radiated energy and a second fraction of thetreatment object radiated energy are incident on the chamber definingmeans bounding the treatment chamber, and the chamber defining meansbeing configured to respond with selective reflectivity to the firstfraction of the heating arrangement radiated energy and the secondfraction of the treatment object radiated energy.

In a continuing aspect of the present invention, a system and method aredescribed for processing a treatment object having a given emissionspectrum at a treatment object temperature which causes the treatmentobject to produce a treatment object radiated energy. A heatingarrangement heats the treatment object using a heating arrangementradiated energy having a heat source emission spectrum at a heat sourceoperating temperature which heat source emission spectrum is differentfrom the given emission spectrum of the treatment object. Sensing meanssenses the treatment object radiated energy at a sensing wavelength.Chamber defining means is used for exposing said treatment object to aportion of the heating arrangement radiated energy while supporting saidtreatment object within a treatment chamber, at least one portion of thechamber defining means is configured for simultaneously (i) respondingin a first way to a majority of the heating arrangement radiated energythat is incident thereon, (ii) responding in a second way to a majorityof the treatment object radiated energy that is incident thereon and(iii) responding in a third way at the sensing wavelength.

In a further aspect of the present invention, a system and method aredescribed for processing a treatment object having a given emissionspectrum at a treatment object temperature which causes the treatmentobject to produce a treatment object radiated energy. A heatingarrangement heats the treatment object using a heating arrangementradiated energy having a heat source emission spectrum at a heat sourceoperating temperature which heat source emission spectrum is differentfrom the given emission spectrum of the treatment object. Sensing meanssenses the treatment object radiated energy emitted by the treatmentobject at a sensing wavelength. Chamber defining means supports thetreatment object during its exposure to the heating arrangement radiatedenergy within a treatment chamber. At least a first portion of thechamber defining means is configured for reflecting a majority of thesensing wavelength that is incident thereon, and at a second, differentportion of the chamber defining means is configured for selectivelyabsorbing a majority of the sensing wavelength that is incident thereon.

In another aspect of the present invention, a system and method aredescribed for processing a treatment object. A heating arrangement isused for heating the treatment object with a heating arrangementradiated energy. Chamber defining means is provided for use in exposingthe treatment object therein to one portion of the heating arrangementradiated energy, while another portion of the heating arrangementradiated energy is incident on the chamber defining means, resulting inan overall radiated energy present within the chamber defining means.The chamber defining means includes a window between the heatingarrangement and the treatment object such that the window is opaque, atleast to an approximation, above an opacity onset wavelength. At least aportion of the chamber defining means includes a selectively reflectiveconfiguration which responds in a first way to a majority of the overallradiated energy incident thereon which is of a shorter wavelength thanthe opacity onset wavelength while responding in a second way to amajority of the overall radiated energy that is incident thereon andwhich is of a longer wavelength than the opacity onset wavelength.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be understood by reference to the followingdetailed description taken in conjunction with the drawings brieflydescribed below.

FIG. 1 is a plot of energy fraction versus wavelength shown here forpurposes of comparing the energy fraction of a radiant lamp heatingarrangement with the energy fraction of radiant energy from a substrate,as wavelength increases.

FIG. 2 is a diagrammatic cross-sectional view, in elevation, of atreatment chamber produced in accordance with the present inventionhaving an inner coated layer, which exhibits a selective reflectivitycharacteristic.

FIG. 3 is a plot of diffuse reflectance against wavelength for a numberof selected materials, which exhibit selective reflectivitycharacteristics that are useful in view of the teachings herein.

FIG. 4 is a diagrammatic cross-sectional view, in elevation, of anothertreatment chamber that is produced in accordance with the presentinvention having a chamber wall arrangement that exhibits desired bulkmaterial ties.

FIG. 5 is a diagrammatic cross-sectional view, in elevation, of stillanother treatment chamber that is produced in accordance with thepresent invention having a chamber wall arrangement that is lined withsheet material members having desired selective reflectivitycharacteristics.

FIG. 6 is a diagrammatic cross-sectional view, in elevation, of stillanother treatment chamber that is produced in accordance with thepresent invention having a chamber wall arrangement, which includes anat least semi-transparent layer that is spaced apart from a chamber wallfor receiving a flowable material therebetween.

FIG. 7 is a diagrammatic cross-sectional view, in elevation, of yetanother treatment chamber that is produced in accordance with thepresent invention having a chamber, which includes a window arrangementthat is interposed between the heating arrangement and the treatmentobject for supporting a flowable material layer.

FIG. 8 is a diagrammatic cross-sectional view, in elevation, of anothertreatment chamber that is produced in accordance with the presentinvention having a chamber, which includes a window that is interposedbetween the heating arrangement and the treatment object having acoating, which serves to isolate a filtering layer from the treatmentobject in order to avoid contamination.

FIG. 9 is a diagrammatic, partial cross-sectional view of a dual layerwindow arrangement, shown here to illustrate the use of thin-filmstacks.

FIG. 10 is a diagrammatic cut-away view, in elevation, of a portion of achamber wall arrangement, produced in accordance with the presentinvention, having an outer wall that is coated with first and secondlayers, which cooperate to provide a desired crossover wavelength.

FIG. 11 is a plot of temperature versus time, shown here for purposes ofcomparing predicted results in the form of the peak width of an annealprocess performed in an unmodified chamber with the peak width for thesame process as performed in a modified chamber in which the lampreflector plate is configured for selective reflectivity.

FIG. 12 is a plot of an idealized spectral response of a selectivereflective coating or material for use in optimizing pyrometry while, atthe same time, providing enhanced system performance with respect towafer heating and cooling.

FIG. 13 is diagrammatic view, in elevation, of a system, having upperand lower lamp arrays, which uses the spectral response shown in FIG.12.

FIG. 14 is a diagrammatic view, in elevation, of another system, havingupper and lower lamp arrays, which uses a highly reflective areaproximate to a pyrometer but which otherwise uses a selective reflectivechamber interior.

FIG. 15 is a plot of an idealized spectral response of a selectivereflective coating or material for use in optimizing pyrometry byreducing stray light entering the pyrometer while, at the same time,providing enhanced system performance with respect to wafer heating andcooling.

FIG. 16 is a diagrammatic view, in elevation, of a system, having singleside wafer heating, which uses a selective reflective chamber interior.

FIG. 17 is a diagrammatic view, in elevation, of another system, havingsingle side heating, which uses a highly reflective area proximate to apyrometer but which otherwise may use a selective reflective chamberinterior.

FIG. 18 is a diagrammatic view, in elevation, of still another system,having single side heating, which uses a selective reflective treatmentof the chamber bottom that is designed to optimize pyrometery results.

FIG. 19 is a wavelength plot of an idealized spectral response of aselective reflective coating that is suitable for treating the chamberbottom of the system shown in FIG. 18, which enhances emissivity at thepyrometer wavelength.

FIG. 20 is a diagrammatic view, in elevation, of another system, havingsingle side heating, which uses a highly reflective area proximate to apyrometer but which otherwise uses a selective reflective chamber bottomthat can be configured, for example, for stray light suppression.

FIG. 21 is a diagrammatic plan view showing a wafer as viewed against achamber bottom, along with multiple pyrometers, which view the chamberbottom; the wafer is rotated for purposes of enhancing processuniformity.

DETAILED DESCRIPTION OF THE INVENTION

In a typical lamp-heated RTP system, it is recognized that limitationson peak width of a heating profile can be attributed to three mainfactors. First, the ramp-up rate is limited by the power available fromthe energy source used to heat the substrate, coupled with theefficiency with which that power is delivered to the wafer surface. Itis noted that tungsten-halogen lamps are used in a number of prior artsystems, however, it is to be understood that the present invention maybe practiced using any suitable heating arrangement and is in no waylimited to the use of such lamps, so long as the teachings herein areapplied. As examples, the present invention contemplates the use offlash lamps and arc lamps. A second limitation arises due to the thermalresponse time of the energy source. For example, in the case wheretungsten-halogen lamps are used as the energy sources for heating thesubstrate, the finite thermal mass of the tungsten filament in this lampis a limitation which governs how fast the lamp can cool and, in turn,limits how fast the power being delivered to the substrate can beswitched off. The third limitation derives from the cooling rate of thesubstrate. The cooling rate is limited by the combination of the thermalmass of the substrate and the efficiency with which heat can be lostfrom the substrate surfaces, typically by thermal radiation or byconvective and conductive heat losses through the process gas thatsurrounds the substrate. As will be seen, the present invention focuseson the first and third of these limitations in a highly advantageous waywhich serves to improve efficiency of coupling heat source radiation tothe treatment object, during operation of the heat source, whileimproving efficiency of heat loss from the treatment objectpost-exposure to the heat source.

The heat transfer to a substrate being heated by lamps in a processingchamber can be approximated by the equation:

$\begin{matrix}{{{\rho\; c\; D\;\frac{\mathbb{d}T}{\mathbb{d}t}} = {{\eta\; P} - {H_{eff}\sigma\; T^{4}}}},} & (1)\end{matrix}$

where T is the absolute temperature of the substrate, t is time, P isthe lamp power density, σ is the Stefan-Boltzmann constant, ρ is thedensity, c is the specific heat capacity, D is the thickness of thesubstrate, η is the fraction of the lamp power coupled to the substrateand H_(eff) is the effective heat loss efficiency. The power may beincident from one side or both sides of the object being heated(processed), and H_(eff) includes the possibility of heat loss from bothsides of the object, as well as the effect of re-reflection of theemitted radiation back onto the object. The terms η and H_(eff) dependon the optical properties of both the substrate and the chamber. Inequation (1), it has been found to be reasonable to assume that T issufficiently high such that the heat transfer is dominated by radiation,and that there are no significant convective or conductive heat lossesfrom the substrate.

While equation (1) can be used to predict the thermal responses ofsubstrates and other treatment objects, when they are subjected toradiant heating, it is recognized that this equation can advantageouslybe used for purposes of understanding what amount to fundamental limitson heating and cooling rates in the contemplated treatment environment.For example, the maximum ramp-up rate, R_(max), can be obtained byrearranging the equation to obtain:

$\begin{matrix}{{R_{\max} = \frac{{\eta\; P_{\max}} - {H_{eff}\sigma\; T^{4}}}{\rho\; c\; D}},} & (2)\end{matrix}$

where P_(max) is the maximum lamp power density available from theheating system. In contrast, a maximum cooling rate, C_(max), is givenby the equation:

$\begin{matrix}{C_{\max} = {\frac{H_{eff}\sigma\; T^{4}}{\rho\; c\; D}.}} & (3)\end{matrix}$

In order to maximize the heating and cooling rates, it is advantageousto design the system so that R_(max) and C_(max), are each as large aspossible. To that end, an inspection of equation (2) shows that for ahigh ramp-up heating rate, it is desirable to make η as high as possibleand to minimize H_(eff). Unfortunately, however, equation (3) suggeststhat a large cooling rate requires maximizing H_(eff). At first blushthen, considering both equations, it appears that maximizing H_(eff) isan interest that competes directly against maximizing R_(max).

The present invention resolves this competing interest, however, byrecognizing that, during a high-speed ramp-up, in what is considered tobe a practical rapid thermal processing (“RTP”) system, the magnitude ofηP_(max). is very much larger than the magnitude of H_(eff)σT⁴. Withthis highly advantageous recognition in hand, system performance can beoptimized by maximizing η and H_(eff). At the same time, it should beappreciated that these quantities are affected by treatment objectproperties. For example, in the instance of an treatment object, it isfurther recognized that such an object's optical properties such as, forexample, those of a semiconductor substrate, are typically defined byspecific manufacturing requirements and may not readily be modified inthe interest of achieving high ramp-up rates and cool-down rates. Suchmodifications, for example, could include making the substrate thinneror the application of surface coatings that emit thermal energy moreefficiently or absorb lamp energy more efficiently. Moreover, it isconsidered to be unlikely that any one substrate treatment will provideuniversal advantages with respect to a particular one of any number ofpossible processing regimes to which that substrate may be subjected. Itis important to understand, in contrast, that the advantages that areprovided by the present invention apply to a broad range of availablesubstrates. That is, the substrate parameters that do influence thepractice of the present invention, over a relatively wide variety ofsubstrates, are generally within a range of variation which produceslittle appreciable difference in a target outcome of the RTP objectivesof the present invention. This is considered as a sweeping advantage, inand by itself, since the present invention requires no modifications asto the substrate, but modifies only the treatment chamber in a way,which provides universal advantages with respect to a broad array ofsubstrates.

In order to optimize system design in accordance with the foregoinghighly advantageous teachings and recognitions, it is useful to considerthose factors in chamber design, which determine η and H_(eff). As onealternative, a high value for η is achieved by making the chamber wallshighly reflective. This result obtains for two reasons. Firstly, energythat is emitted from the lamps in the direction of the chamber wall canreflect back, towards the substrate. High reflectivity walls absorblittle energy and advantageously return much of the lamp radiation inthe direction of the substrate. Secondly, the lamp energy that isreflected from the substrate surface will be re-reflected by the chamberwall and can have continuing opportunities to be absorbed by thesubstrate. In the limiting case of a perfect chamber reflector, all ofthe lamp energy would be absorbed by the substrate.

If the walls are reflecting, so as to provide the aforedescribedadvantages with respect to the lamp radiation, then energy emitted bythe substrate will likewise be re-reflected back onto the substratesurface, thereby disadvantageously reducing the net heat loss withrespect to cooling the substrate. In the limiting case of perfectlyreflecting walls, the substrate would not be able to lose heat byradiation.

As another alternative, a high value for H_(eff) is achieved by makingthe chamber walls highly absorbing. If the walls are perfectly black,then none of the energy lost by radiation from the substrate surface canreturn to the substrate. However, in this instance, lamp radiation isdisadvantageously absorbed.

It is noted that the prior art has generally opted for one or the otherof these two alternatives, even though performance is compromised withrespect to the non-elected alternative. In some instances, individualchamber and component surfaces within a particular treatment system havebeen selectively configured in accordance one of these alternatives inorder to accomplish specific objectives with respect to the particularsurface that is of concern. For example, heat sensitive components canbe coated so as to be highly reflective, whereas reflector plates can beblack for purposes of conducting heat away from the treatment chamber.The present invention, however, recognizes that these apparentlyconflicting requirements, as defined by these two essentially oppositealternatives, can be resolved in a highly advantageous way, as will beseen below.

As one example of a highly reflective prior art arrangement, aluminumchamber walls have been used including a polished surface. Such apolished surface can receive a plating using, for example, gold. Asanother example, a matte aluminum surface can be plated with gold(resulting in a matte gold finish). With respect to polished aluminum(with or without gold), it is submitted that small changes in thequality of the polished surface result in large differences inreflectivity, which then results in chamber to chamber performancedifferences. A matte gold finish appears to provide more consistentresults in terms of chamber to chamber consistency. Both aluminum andgold, however, are broad band reflectors, as will be further described,in that they have high reflectivity in both the visible and in the nearand mid-infrared regions of the energy spectrum.

Attention is now directed to FIG. 1 which is a plot of Energy Fractionagainst increasing wavelength, shown here to illustrate the fraction ofenergy emitted below a specified wavelength, for the cases of blackbodyradiators at temperatures of approximately 3200°K and 1373°K, whereinthe plots are referred to by the reference numbers 10 and 12,respectively. The higher temperature of 3200°K, for plot 10, isrepresentative of the temperature of the filaments in a W-Halogen lampthat may be used in an RTP system. The lower temperature of 1373°K, forplot 12, is representative of the temperature of a substrate at the peakpoint of a spike anneal process at 1100° C. Specifically, it isrecognized that the emission spectrum from the substrate and heatingarrangement such as, for example, Tungsten-Halogen lamps, are quitedifferent. Consistent with this recognition, it is further recognizedthat a chamber wall that is simultaneously highly reflecting for thelamp radiation and highly absorbing for the radiation emitted by thesubstrate provides heretofore unseen advantages. The key, in thisregard, is to make the chamber behave with “selective reflectivity”,i.e., its reflectivity varies with wavelength. In essence, the use ofsuch selective reflectivity materials presents a first reflectivityprofile to the heating arrangement energy while presenting a second,different reflectivity profile to the substrate radiated energy, as willbe further described.

The reflectivity of an object is often, at least to some limited extent,a function of the wavelength, λ, of the electromagnetic radiationincident on it. The variation of reflectivity with wavelength isdescribed by the function R(λ) that depends on the optical properties ofthe materials comprising the object and the physical structure of theobject. This variation with wavelength is described as the reflectionspectrum of the object.

Any electromagnetic radiation source, including any thermal energysource, has an emission spectrum, S(λ), that describes the power emittedby the source at any given wavelength. In a small wavelength range Δλaround the wavelength λ, the source emits a power S(λ)Δλ. The powerradiated by the source in any wavelength interval can be calculated byintegrating the emission spectrum over the wavelength range of interest,for example from λ₁ to λ₂:

$\begin{matrix}{P_{\lambda_{1},\lambda_{2}} = {\int_{\lambda_{1}}^{\lambda_{2}}{{S(\lambda)}{{\mathbb{d}\lambda}.}}}} & (4)\end{matrix}$

The total power radiated by the source is obtained from the integral

$\begin{matrix}{P_{{source},{total}} = {\int_{0}^{\infty}{{S(\lambda)}{\mathbb{d}\lambda}}}} & (5)\end{matrix}$

When radiation from this energy source falls on an opaque object, theradiation can be reflected or absorbed. The amount of power that isreflected at any given wavelength is determined by the product of thespectral reflectivity and the incident power. Hence the total powerreflected in the wavelength range from λ₁ to λ₂ is given by theintegral:

$\begin{matrix}{P_{{reflected},\lambda_{1},\lambda_{2}} = {\int_{\lambda_{1}}^{\lambda_{2}}{{R(\lambda)}\;{S(\lambda)}{{\mathbb{d}\lambda}.}}}} & (6)\end{matrix}$

A total reflectivity, R_(tot, S) is defined for the object with respectto the radiation from the source S, as equaling the ratio of the totalpower incident on the surface to the total power reflected from thesurface:

$\begin{matrix}{R_{{total},S} = {\frac{P_{{reflected},{total}}}{P_{{source},{total}}} = {\frac{\int_{0}^{\infty}{{R(\lambda)}{S(\lambda)}{\mathbb{d}\lambda}}}{\int_{0}^{\infty}{{S(\lambda)}{\mathbb{d}\lambda}}}.}}} & (7)\end{matrix}$

It should be emphasized that this integrated property, R_(total, S), isa function of both the object and of the illumination spectrum.

The concept of selective reflection arises in a situation such as iscontemplated by the present invention, wherein an object interacts withradiation from two energy sources A and B, with spectra SA(λ) and SB(λ)respectively. Two total reflectivities can be defined with respect tothese two spectra, R_(total,SA) and R_(total,SB) through the use ofequations similar to (7). In this example case, the source spectra SA(λ)and SB(λ) may be quite different, so in generalR_(total,SA)≠R_(total,SB). If there is a significant difference betweenthe two quantities, then the object can be said to show selectivereflection behavior with respect to energy source A and source B.

Typically, useful selective reflectors have reflection spectra thatinclude large variations in reflectivity as the wavelength varies. Forexample, the reflectivity may be high in one wavelength range and thenfall to a low value in a second wavelength range. In this case, it isrecognized that, if source A predominantly radiates energy in the firstwavelength range and source B predominantly radiates energy in thesecond wavelength range, then the total reflectivity will be high forsource A and low for source B and the object is considered by thepresent invention as a selective reflector.

This concept is equally applicable with respect to the absorption ofradiation. Equivalent properties can be developed for absorbtivity atany wavelength, and for integrated absorbtivity that describes the totalpower an object absorbs in a given wavelength range when illuminated bya given energy source. An object that exhibits significant differencesin its absorption behavior with respect to two energy sources is aselective absorber. Typically, this behavior arises when the object hashigh values of absorbtivity in one wavelength range and a low value in asecond range.

The concept of selective emission may also be employed. According toKirchhoff's law, the absorptivity and emissivity at any given wavelengthmust be equal. This law applies for identical optical conditionsincluding wavelength, incident angle and polarization state. As aresult, a selective absorber will usually emit significantly morethermal radiation in one wavelength range than it does in a secondwavelength range. This behavior may be referred to as selectiveemission.

Still considering FIG. 1, it is evident that greater than 75% of theradiation from the lamp heating arrangement is emitted at wavelengthsless than 2 μm, whereas greater than 75% of the radiation from thesubstrate is emitted at wavelengths greater 2 μm. Hence, a reflectorthat has a high reflectivity for wavelengths of less than approximately2 μm and a low reflectivity for wavelengths greater than approximately 2μm simultaneously provide a high value for η and yet a low value forH_(eff). The wavelength selection or breakover point for a particularchamber peripheral arrangement can be referred to as a “crossover”wavelength. In the present example, the 2 μm crossover wavelength isdesignated by the reference number 14. Below the crossover point, thechamber walls (or at least some portion thereof) reflect a majority ofthe heating arrangement emitted energy incident thereon while, above thecrossover point, the chamber walls absorb a majority of the substrateemitted energy incident thereon.

With respect to this advantageous dual behavior, it is important torealize that any suitable wavelength can be selected for the crossoverwavelength, depending on the desired results. In some applications,where only modest increases in cooling rate are desired, it may bedesirable to make a crossover between high and low reflectivity at alonger wavelength, for example, approximately 3 μm. In other cases,maximization of the cooling rate may be more important and the crossoverwavelength could be shifted for example to 1.5 μm. If the energy sourceis, for example, an arc lamp, then most of the emission spectrum is atmuch shorter wavelengths and the crossover could be at 1 μm, withouthaving a detrimental effect on the heating rate. More particularly, thechamber may exhibit a high reflectivity at relatively short wavelengths(for example, less than approximately 2 μm wavelength) where the heatingarrangement emits most of its energy and a low reflectivity atrelatively long wavelengths (for example, greater than approximately 2μm wavelength) where the substrate emits most of its energy.

With respect to chamber walls, it is recognized that both aluminum andgold are broad band reflectors in both the visible and in the near andmid-infrared regions of the energy spectrum. Further, the far infrared(above approximately 8 μm) is not of great concern, in the instance of asemiconductor substrate or wafer, as the amount of wafer energy in thatregion is less than 10% of the energy emitted by the wafer, when thewafer has been heated to a temperature typically used for rapid thermalprocessing. Still further, the amount of lamp energy in the far-infraredis typically less than 5% of its total emitted energy.

Having described the recognitions above that have brought the presentinvention to light, attention is now directed to a number of differentembodiments for use in its practice. To that end, attention is initiallydirected to FIG. 2 which diagrammatically illustrates a first embodimentof a treatment system that is produced in accordance with the presentinvention and generally indicated by the reference number 50. System 50includes a heating arrangement 52 that is made up of a plurality ofTungsten-Halogen lamps, only one of which lamps is shown for purposes ofclarity. Again, it is to be understood that any alternative heatingarrangement is considered to be within the scope of the presentinvention so long as the teachings herein are applicable. As oneexample, the use of an arc lamp heating arrangement is contemplated. Asanother example, another heating arrangement is often positioned belowthe treatment object in the elevational view of this figure, which hasnot been shown for purposes of clarity. Lamp 52 emits a radiant energy54 consistent with plot 10 of FIG. 1. This heating arrangement emittedenergy is illustrated using arrows having a stem which alternates at arelatively short wavelength. It is noted that like reference numbershave been applied to like components throughout the various figureswherever possible. Moreover, it is to be understood that terminologythat is applied with reference to the views of one or more of thefigures such as for example “frontmost”, “rearmost”, “upper”, “lower”,“outer” and “inner” is used solely for purposes of descriptive clarityand is in no way intended as being limiting. Further, it is noted thatthe drawings are not to scale and have been presented in a way that isintended to enhance the reader's understanding.

Still referring to FIG. 2, system 50 further includes a chamberarrangement 60 which defines a treatment chamber 62 for receiving andsupporting a treatment object 64 therein. Treatment object 64 maycomprise, for example, a semiconductor substrate, as described above.The substrate may be supported, for example, on a conventional pedestal(not shown). Treatment chamber 60 is shown in cross-section and isconfigured in accordance with the present invention having an outer wallarrangement 65 supporting an inner layer 66 which surrounds an interiorperiphery. Wall arrangement 65 may be formed, for example, usingaluminum having a thickness that is sufficient to ensure structuralintegrity. It is noted that a “wall arrangement”, as well as the terms“wall” and “wall member”, as used throughout this disclosure and theappended claims, are not intended to encompass a window which may beinterposed between the heating arrangement and the treatment object.Once heated to an appropriate temperature, treatment object 64 emits atreatment object radiated energy 68 having a relatively long wavelength,as compared to radiant energy 54 from heating arrangement 52.

Continuing to refer to FIG. 2, inner layer 66 may be formed, in oneimplementation, using any suitable material as a coating in view of thereflectivity of the selected material. The coatings can be applied byany number of well known methods including painting, spraying, plasmaspraying or other deposition methods. Applicants formulated and tested anumber of coatings. Candidate materials were selected based on diffuseand specular reflectivity. Additionally, the ability to readilyformulate coatings, using a selected material, played a factor in theselection process. Accordingly, the list of appropriate materialspresented herein is not considered to be exhaustive but, rather,exemplary.

Referring to FIGS. 2 and 3, the latter illustrates diffuse reflectanceof various coated samples for selected formulated coating materials,plotted against wavelength in μm. While diffuse reflectivity isillustrated, it was found that the diffuse and specular reflectivitiesboth exhibit general drops at approximately the same wavelength andwithin the region of interest. Accordingly, the wavelength response isproperly characterized in terms of general reflectance. A plot 80corresponds to aluminum oxide. This plot, along with the remaining plotsof FIG. 3, was obtained from infra-red reflection spectroscopymeasurements. Aluminum oxide was demonstrated to be useful in forminglayer 66 for a number of reasons, when applied as one of the testedcoatings, using a plasma spray. First, the aluminum oxide layer becomesmechanically and chemically bonded to an underlying aluminum chamberwall. As such, the coated layer is very adherent to its metal substrate.Second, aluminum oxide is a totally inorganic oxide and, therefore, itwill not oxidize in a hot atmospheric environment—its optical propertieswill not drift or change appreciably over time. It should be noted,however, that aluminum oxide can, at least potentially, becomecontaminated due to the absorption of contaminants that may be present,for example, in air that is used to cool the W-halogen lamps.Accordingly, such contaminants should be rendered unavailable in thecooling air. Third, an aluminum oxide coating does not require postapplication processing. Fourth, coating properties are considered to bevery repeatable from application cycle to application cycle. Fifth, thecoating can be applied very thin (at a thickness from approximately 1 nmto 1.5 millimeter) and, as such, it does not appreciably change theability of a component such as, for example, an aluminum reflectorplate, which backs lamp arrangement 52, to extract heat absorbed by thecoating. Thus, the coating is allowed to operate at a temperature of nomore than approximately 120 degrees C., thereby minimizing stressbetween the coating and the substrate to which it is applied. It isnoted that a lamp reflector plate is represented by an upper wallportion 66 a of overall layer 66 which coats the chamber wall nearestlamp arrangement 52. In this regard, it should be appreciated that thereis no requirement to coat all of the interior chamber walls. Moreover,it is to be expected that coating 66 a provides for maximized returns inthe event that it is desired to coat only a portion of the chamberinterior, since it most directly confronts the major/treatment surfaceof treatment object 64, as well as directly confronting heatingarrangement 52, so as to be intensely exposed thereto.

It is considered that a diffuse selective reflective coating should bemore uniform, in terms of its optical response, than a polished surfacesuch as, for example, polished aluminum. Obtaining a polished aluminumsurface that is sufficiently optically uniform across its entire surfaceis difficult. This result obtains at least for the reason that evensmall changes in the surface roughness can cause significantnon-uniformity in terms of optical response. A bare polished aluminumsurface is sensitive to corrosion, as well as surface contamination.Moreover, it is a soft surface and is easily scratched. Anycontamination that is absorbed onto the surface will also affect itsoptical properties, likely in a non-uniform way. In contrast, a diffuseselective reflective coating should generally be more stable in terms ofcorrosion and contamination resistance, depending on the exactcomposition of the coating material. In the case of plasma sprayedaluminum oxide, the coating is essentially a ceramic coating and iscomparatively extremely stable and generally insensitive tocontamination. Moreover, an aluminum oxide plasma coating exhibitsscratch resistance.

The remaining plots in FIG. 3 correspond to materials that weregenerally formulated as paints and tested as described above. Thesematerials can be provided having any suitable thickness, for example, ina range from about 0.01 mm to 1.5 millimeter. It was found that theseparticular white paints introduce the desired wavelength selectioneffect, although there is no need for the paint to appear white.Specifically, plot 82 corresponds to Titanium dioxide (TiO₂); a plot 84corresponds to Zirconium silicate (ZrSiO₄); a plot 86 corresponds toZirconium dioxide/Yttrium oxide (ZrO₂/Y₂O₃); and a plot 88 correspondsto Titanium dioxide/silicon dioxide (TiO₂/SiO₂). The paint that was usedto carry these various materials was formulated using organic andinorganic binders. It is submitted that one of ordinary skill in the artmay readily devise any number of such formulations for purposes ofapplying these materials in a coating, in view of this overalldisclosure. Each paint was then spray applied to an aluminum base plate.The organic binder was then burned out in an oven at approximately 400degrees C., so that only the materials of interest remained, along witha very small fraction by weight of the inorganic binder.

It is readily observed in FIG. 3 that each reflectance plot for thesevarious materials exhibits a significant drop in reflectance between 2μm and 3 μm in wavelength. Moreover, the reflectance for each plot, ingeneral, does not fully recover with further increasing wavelength.Accordingly, these materials, or combinations thereof, are allconsidered as useful candidates for forming inner layer 66. A usefulmaterial should exhibit a general drop in reflectivity in the wavelengthrange from about 1 μm to 10 μm. Materials which exhibit a drop in anarrower wavelength range from about 2 μm to 3 μm are considered to beparticularly useful. A crossover at about 2 μm is particularly usefulwith the use of Tungsten-Halogen lamps, as demonstrated by FIG. 1.

Other materials are also considered as important including, but notlimited to Potassium Di-hydrogen Orthophosphate, Aluminum OrthophosphateMagnesium Pyrophosphate, Boron Phosphate and Yttrium Phosphate. Coatingsusing these materials, for purposes of serving as selective reflectors,are preferred to be diffuse (matte) in order to improve chamber tochamber matching.

Generally, a useful coating may contain atomic bonds, potentiallyintroduced as impurities, that are known to introduce absorption ofinfrared energy at the wavelengths of interest. For example, it is knownthat the O—H bond, and associated Si—O—H and Al—O—H bonds introducestrong absorption features and, consequently, low reflectivity atwavelengths in the near IR, especially between 1.4 and 3 μm. Materialsthat incorporate water, either directly as H₂O or in some otherconfiguration, are also likely to exhibit this useful characteristic.The effects of hydrogen bonding can also provide useful spectralfeatures. Other bond groups that introduce useful spectral featuresinclude carbonates, CO₃, nitrates, NO₃, and bonds between elements andhydrogen, for example C—H bonds and N—H bonds. Di-hydrogen potassiumphosphate also has a very sharp cut-off at approximately 2 microns.

In many instances, the white characteristic of a coating arises from themain constituent material being transparent at visible wavelengths.These materials appear white because they are present in a finelydivided form that greatly increases the scattering of light. The bestanalogy here is between a large block of ice, which is transparent, andsnow, which is bright white. The coating properties then frequentlycombine the desirable characteristic of being a material that is highlytransparent at wavelengths below the crossover wavelength, and absorbingat wavelengths greater than the crossover wavelength. Examples ofsuitable materials that are inherently transparent in the lamp radiationband are SiO₂, Al₂O₃ and TiO₂, although there are many others. It isimportant to realize that many of these materials exhibit usefulabsorption features only as a result of the presence of introducedimpurities, as mentioned above. In many cases, the properties can beoptimized by blending components that are transparent with others thatare absorbing. It can also be useful to optimize the size and therefractive index of the grains of material that produce the lightscattering, as well as the absorbing effects.

Referring to FIG. 2, it should be appreciated that the ratio of energyreflected above and below the crossover wavelength, for example, 2 μmcan also be tuned by adjusting the surface roughness of a particularcoating or the surface of a bulk material having selective reflectivityproperties, yet to be described.

Other materials that contain strong absorption features that may beuseful include metal oxides as well as other crystals, ceramics and evenplastics. These materials can also be prepared in forms that maximizetheir reflectivity in the short-wavelength band. For example, a polymerlayer may be used. Suitable polymers include, but are not limited tofluoropolymers and chloro-fluoro-polymers with or without fillermaterials. These polymers include, for example, polytetrafluorethylene,ethylene-tetrafluorethylene, ethylene-trifluoroethylene, fluorinatedethylene propylene, ethylene-chloro trifluoroethylene, polyvinylidenefluoride, polychlorotrifluoroethylene, perfluoroalkoxy, relatedmaterials and combinations thereof. A polymer based layer may includefiller materials including, but not limited to aluminum oxide particles,titanium dioxide particles, mixtures of aluminum dioxide and titaniumdioxide particles, glass particles, glass fibers, and other fillermaterials that are capable of modifying the optical reflectivity of anappropriate base polymer.

Referring to FIG. 4, another embodiment of a system, produced inaccordance with the present invention, and generally indicated by thereference number 90, includes a chamber arrangement that is formed ofbulk materials with the desired properties, rather than using an appliedcoating. One example is the use of an opaque quartz (fused silica) wallarrangement 92 that includes a high concentration of OH bonds. Theopaque quartz is quartz that includes a very large density ofmicroscopic bubbles that strongly scatter light, giving it a brightwhite appearance. This is an alternative approach for turning aninherently transparent material such as quartz, into a highly reflectingobject that looks white. By incorporating OH bonds or other impurities,strong absorption features can be created at wavelengths beyondapproximately 2 μm. As another example, the chamber walls may be formedusing alumina which essentially comprises a bulk ceramic material.

Turning to FIG. 5, another embodiment of a system, produced inaccordance with the present invention, and generally indicated by thereference number 98, uses an arrangement of one or more members of sheetmaterial to line one or more interior peripheral surfaces of outer wallarrangement 65. In the present example, an arrangement of five sheetmembers is indicated using the reference numbers 100 a-e (which may bereferred to collectively as sheet members 100), wherein sheet 100 e issupported against the rear wall of the chamber in the view of thefigure. The frontmost wall of the treatment chamber is not visible inthe present view, but may likewise support a sheet material member. Theapproach of this embodiment is advantageous with respect to allowing theuse of underlying metal structural walls in forming an overall cooledisolation barrier. Again, there is no requirement to line, or treataccording to any embodiment described herein, every interior chambersurface. For example, only the upper surface could be treated. Further,there is no requirement to cover the entirety of any one surface. Forinstance, only that portion of the upper surface which is immediatelyadjacent to the heating arrangement could be coated or otherwisetreated. It is considered that one useful embodiment is provided by anychamber implementation having 20 percent or more of the chamber interiorsurface configured to provide for selective reflection. In this regard,it should be remembered that selectively reflective chamber surfacesthat are at least generally parallel to and, in particular, confronting,the major surface of a treatment object, are likely to provide anenhanced response with respect to the benefits realized by the practiceof the present invention. Moreover, the various embodiments describedherein may be combined in any suitable manner.

Continuing to refer to FIG. 5, still another embodiment, which isessentially identical in appearance to that embodiment describedimmediately above, resides in using outer chamber walls 65, formed usingmetal, as a short wavelength reflector. In this instance, the materialfrom which sheet members 100 a-e are then formed is selected to beessentially transparent at short wavelengths, yet opaque at longerwavelengths in a way which provides an appropriate crossover wavelength.It is noted that materials that are referred to herein as transparentare understood to provide for light transmission in a contemplatedwavelength range at least to an acceptable approximation. Sheet members100 act as a filter that absorbs the long wavelength radiation, whileallowing the chamber wall to carry on serving as a high reflectivityreflector for the lamp radiation. It is desirable for the sheet membersto be transparent, for example, at less than approximately 2 μm andopaque at approximately greater than 2 μm in wavelength, although it isto be understood that this crossover wavelength has been selected as onepossible value, that is useful and is in no way intended as beinglimiting in any embodiment described herein. It is noted that someglasses come at least acceptably close to this requirement, and can alsoexhibit the benefit of a low surface reflectivity. For example, somerare-earth doped glasses have strong absorption bands in the nearinfrared that could provide suitable absorption features. Even glassessuch as, for example, Pyrex, that cut off most radiation for wavelengthsgreater than 2.5 μm, may be suitable. Suitable rare-earth doped glassesand associated methods are described in co-pending U.S. application Ser.No. 10/288,272, filed on Nov. 5, 2002, entitled APPARATUS AND METHOD FORREDUCING STRAY LIGHT IN SUBSTRATE PROCESSING CHAMBERS, which is commonlyassigned with the present application and is hereby incorporated hereinin its entirety by reference.

Attention is now directed to FIG. 6 which diagrammatically illustrates atreatment system, produced in accordance with the present invention andgenerally indicated by the reference number 120. System 120 includes achamber wall 122 as part of an overall chamber wall arrangement thatserves to define treatment chamber 62. In the present example, onlychamber wall 122 has been illustrated for purposes of clarity, althoughsuch walls are understood to be arranged in a way which surrounds thetreatment chamber, as shown in previously described figures. Chamberwall 122 further serves as a reflector plate for heating arrangement 52.An at least semi-transparent layer 124 is supported in a spaced apartrelationship from chamber wall 122 so as to define a void or channel 126therebetween. While layer 124 of the present example is transparent, insome embodiments, this layer may include a degree of selectivereflectivity or absorbance. Spacers (not shown) or any other suitablemechanism of the many that are known in the art may be used formaintaining this spaced apart relationship. Channel 126 receives a flowof a flowable material 128 that is indicated by a number of arrowswithin the channel. This flowable material may be referred tointerchangeably as fluid and may advantageously serve in a heat transferrole, whereby system 120 is cooled. The flowable material may comprise aliquid or a gas, as desired.

Even more advantageously, however, flowable material 128 serves as afiltering element with respect to at least one of lamp radiation 52 andsubstrate emitted radiation 68. In this regard, it should be observedthat heating arrangement radiant energy is illustrated as reflectingfrom chamber wall 122 through flowable material 128, while treatmentobject radiated energy 68 is illustrated as being absorbed by flowablematerial 128. In one feature, the fluid may include water. One advantageof this feature resides in the fact that water is a very strong absorberof infrared radiation at wavelengths greater than approximately 1.4 μm,and hence can form a useful selective reflector, in combination, forexample, with any broadband reflector serving as a chamber wall. Ofcourse, the chamber wall could additionally be lined or coated, asdescribed above and may serve as a reflector plate, backing the heatingarrangement. A lined chamber wall configuration can appear similar tothe lined chamber of FIG. 5 accompanied by one or more semi-transparentlayers 124 (FIG. 6) in a spaced apart relationship with the linedchamber walls. Again, it is noted that selective reflection, backing theheating arrangement (i.e., as a reflector plate), is considered toprovide the greatest benefit where there may be some motivation not tocover or treat the entire interior periphery of the chamber such as, forexample, system cost. In implementations having a heating arrangementbelow the treatment object, a significant benefit is likewise expectedby using a similar water layer carrying arrangement beneath thetreatment object.

In many prior art RTP systems, the treatment object faces a quartzwindow that isolates it from the heating lamps. It is recognized thatthis window itself provides a degree of spectral selectivity, since itis generally opaque for wavelengths longer than approximately 3.7 μm,and transparent at shorter wavelengths. Moreover, the window exhibits atransition region that extends from practical transparency to practicalopacity. The center of the transition region may be considered as anopacity onset wavelength. Hence, the window acts as a filter, in amanner which introduces selective reflection properties, rather like thelining of the embodiment of FIG. 5. However, there is an importantdifference, as compared to a chamber surface, wall or lining, since thewindow also filters all of the heating arrangement emitted radiationwhich ultimately reaches the wafer. Hence, the window will significantlyimpact efficiency of energy transmission to the treatment object fromthe heating arrangement. In the instance in which the window is watercooled, relatively large energy loss is expected for at least somesources, as noted above, since water is a very strong absorber of IRenergy for wavelengths greater than 1.4 μm. Accordingly, water-cooledwindows are mainly expected to be useful in conjunction with shorterwavelength heat sources such as, for example, arc-lamp sources that emitmost of their energy below this wavelength. With these recognizedconstraints now in view, it is considered that window arrangements canbe implemented and used with benefit. For example, if a window is formedof a material with absorption that becomes strong at wavelengths greaterthan 2 μm, it is considered as likely to be useful. As an alternative toa window supporting a water layer, it is recognized that theaforementioned rare-earth doped glasses, having strong absorption bandsin the near infrared, may be employed in window arrangements that aremade up of one or more layers. Moreover, glasses such as, for example,Pyrex, that cut off most radiation for wavelengths greater than 2.5 μm,may be suitable.

In connection with the discussion of windows, it is appropriate at thisjuncture to note that some materials may not be acceptable for forming achamber wall or coating thereof because these materials may not be aschemically stable or as pure as might be desired in directly facing thesubstrate and/or being resident with the substrate in a common treatmentchamber, although these materials may exhibit extremely desirablecharacteristics.

Turning now to FIG. 7, attention is now directed to another system,produced in accordance with the present invention and generallyindicated by the reference number 140. System 140 includes a chamberwall 141 as part of an overall chamber arrangement. In the presentexample, only chamber wall 141 has been illustrated for purposes ofclarity, although such walls are understood to be arranged in a waywhich form the chamber arrangement. Chamber wall 141 further serves as areflector plate for heating arrangement 52, and may optionally include aselective reflectivity characteristic, as described above, so as togenerally reflect heating arrangement radiated energy 54, whilegenerally absorbing treatment object radiated energy. Of course, otherwalls may be partially or fully configured for selective reflection, inaccordance with the present invention. A window arrangement 142 isinterposed between heating arrangement 52 and treatment object 64. Inthis case, window arrangement 142 may include a double window structurewherein a filtering element 144 is positioned nearest heatingarrangement 52. In one implementation, a transparent window 146 isspaced apart from filtering element 144 so as to form a passage 148between itself and the filtering element. Passage 148 permits flow of acoolant 150, indicated using arrows, either gas or a liquidtherethrough. As mentioned above, water can be used as the coolant,depending, for example, upon the wavelength characteristics of theheating arrangement. Further discussions of suitable fluidcharacteristics are given at an appropriate point below. It should beobserved that heating arrangement radiant energy 54, in addition toreflecting from selective reflecting wall 141, is illustrated as passingthrough window arrangement 142, while treatment object radiated energy68 is illustrated as being absorbed by flowable material 150. Theoverall response of the window arrangement, like any window arrangementdescribed herein, may be characterized as decreasing transmissivity withincreasing wavelength. Further, any energy 151, generally within thewavelength range that encompasses the treatment object radiated energy,and which reaches wall 141, will generally be absorbed by wall 141 inserving as a reflector plate although this is an optional configuration,not a requirement. It is noted that energy 151 could arise, for example,as a small portion of the heat source radiated energy, a portion oftreatment object radiated energy which escapes absorption in windowarrangement 142 and/or a portion of energy that is radiated by a windowarrangement, such as window arrangement 142, upon being heated. It is tobe understood that a single plate member may be employed as a windowarrangement, while the teachings herein are applied. Further, withrespect to any embodiment described herein, it is to be understood thatan additional heating arrangement may be positioned below the treatmentobject, which may employ an additional window arrangement supportedbetween the additional heating arrangement and the treatment object,which has not been shown for purposes of clarity.

In another implementation, which is readily visualized in view of FIG.7, filter element 144 is moved into direct contact with transparentwindow 146 so as to eliminate passage 148, at least from a practicalstandpoint. The function of the transparent window is to serve as aprotective barrier to prevent any component of the filtering layer frompotentially contaminating the substrate. That is, the filtering elementis not in contact with the substrate-processing environment of thetreatment chamber. Heat transfer between transparent window 146 andfilter element 144 may occur mainly by conduction, either through a gasor a layer of transparent cement which can be used for attachmentpurposes.

The transparent window in either of the foregoing implementations may beformed, for example, from fused quartz. With respect to filter element144, any suitable material or combination of materials may be used inthese implementations, or any embodiment disclosed in this overalldisclosure, with no limitation to the specific materials describedherein which exhibit selective reflectivity.

Referring to FIG. 8, in still another embodiment of the presentinvention, generally indicated by the reference number 160, filteringelement 144 may receive a coating which serves as aprotective/transparent layer 162 that is functionally equivalent totransparent window 146. There are a number of materials that could beused as a protective/transparent layer including, but not limited toSiO₂, Al₂O₃ and YAG. The protective layer can be applied to filter layer144 by any number of suitable techniques such as, for example,evaporation, sputtering, ion plating and dip coating. It is to beunderstood that any window arrangement described herein can be used, asan option, with any selective reflectivity wall arrangement disclosedherein.

In connection with FIGS. 6 and 7, there can be advantages to usingdeuterium oxide (D₂O, heavy water) rather than normal water. D₂O has aninfrared absorption spectrum that includes features similar to the H₂Oabsorption spectrum, except that they are shifted to longer wavelengths.This moves the strong absorption cut-off to wavelengths greater thanapproximately 2.0 μm. Accordingly, such an implementation is consideredto be advantageous due to an attendant reduction in the absorption oflamp radiation. Further, the use of the species HDO, deuterated water,is contemplated having an absorption spectrum that lies between that ofH₂O and that of D₂O. As noted above, H₂O may not be ideal, for example,as a window cooling fluid when the energy source is an array ofW-halogen lamps. D₂O, however, can be used in this application with farless energy loss.

It is further noted that any absorbing system that relies on absorptionarising from bonds to hydrogen can be modified by deuteration, so thatthe bonds to hydrogen are replaced by bonds to deuterium. Asnon-limiting examples, the absorption spectrum of silica glass could bealtered through the introduction of O-D bonds rather than OH bonds andorganic materials containing C—H bonds could be altered to C-D bonds.

Having described the wavelength response of a quartz window above, it isimportant to understand that the selective reflective surface chamberconfiguration of the present invention will also absorb heat that wouldotherwise heat the quartz window that normally separates the tungstenlamps from the wafer process environment. That is, the amount ofradiation which attempts to pass through the window, at wavelengths thatwill be absorbed, is reduced. As another effect, the selective reflectorsurface configuration can absorb thermal radiation that is emitted by awindow itself (for a quartz window this is mainly at wavelengths greaterthan approximately 3.7 μm, i.e. in the region where the window isgenerally opaque and does not transmit lamp or wafer radiation). In thiscase, radiation emitted by the window, after it has been heated, is notre-reflected back onto the window by the chamber wall, leading to alower window temperature. It is important to note that for a selectivereflector to function solely in this manner does not require a crossoverin reflection/absorption behavior at 2 um, since one wavelength foreffective window cooling action is defined, at least approximately, bythe opacity onset wavelength, e.g. typically at approximately greaterthan 3.7 μm for quartz windows. Accordingly, a crossover wavelength fora selective reflector, used in this manner, may be selected as anysuitable wavelength chosen in relation to the opacity transition regionof the window. As an example, higher or lower figures with respect tothe opacity transition region of the window are considered useful solong as the function of the selective reflector is consistent with theteachings herein for purposes of window cooling. Of course, the twobenefits of improved wafer cooling and improved window cooling can becombined as taught herein, but that is not a necessity for eitherbenefit to be employed independently.

In view of the foregoing, the use of a selective reflector configurationis highly advantageous with respect to reducing the magnitude of thetemperature change a window such as, for example, a quartz window,experiences as consecutive wafers are processed. In and by itself, theprogressive increase in the temperature of the window results ininconsistent processing results. The present invention reduces themagnitude of the window temperature change, thereby reducing the “firstwafer effects” and improving process uniformity during a period of timeover which the window is heating up. At the same time, the effect of thewindow on wafer temperature uniformity is reduced so as to providehigher uniformity in wafer temperature. That is, the temperaturedifferential laterally across the window width is reduced. Benefits ofimproved window cooling include: (a) less first wafer effects, (b)improved wafer uniformity as a result of less re-radiation of heat froma cooler window, and (c) more rapid cooling of the wafer, because lessheat is transferred back to the wafer (by any of radiation, conduction &convection) as a result of the presence of a relatively cooler window.The latter point is especially relevant when the wafer has cooled downto a temperature relatively near the window temperature although somebenefit is provided, as well, at high temperature.

Referring again to FIG. 2, another class of coatings that can be used tocreate selective reflectors are those formed from single or multilayerthin-film coatings. Accordingly, inner layer 66 may include a thin filmcoating arrangement, which may cooperate with wall arrangement 65 toprovide a desired overall response. Thin-film coatings are designedaccording to optical principles that allow design for maximization orminimization of reflectivity at a selected wavelength, selectedwavelengths or over a wavelength band and are frequently used in opticalfiltering applications. It should be appreciated that such coatings canbe formed as thin as 1 nm. Accordingly, wall arrangement 65 isconfigured, in such an embodiment, to absorb at least the wavelengthsthat are not reflected. Multilayer thin-film stacks can be created asdesired, based on specified objectives such as decreasing reflectivitywith increasing wavelength, and are usually formed by methods ofphysical vapor deposition or chemical vapor deposition. In accordancewith the present invention, it is considered that one having ordinaryskill in the art can tailor a design, in view of this overalldisclosure, to achieve high reflectivity at wavelengths below a desiredcross-over wavelength and low reflectivity at wavelengths above thedesired cross-over wavelength. Thin-film coatings can be applied to mostmaterials including metal surfaces, windows, and other parts in theprocessing equipment, as desired. Such coatings are often used in theconstruction of a “cold mirror.” The latter is a coating component thatis sometimes used for isolating heat in projection systems. Suchexemplary coatings have the characteristic of reflecting visible lightwhile transmitting and/or absorbing infrared energy. The presentinvention, however, requires a crossover wavelength in the IR, ratherthan at the edge of the visible spectrum. That is, a modified form of acold mirror can be used in combination with an underlying, absorbingsurface such that that energy is not reflected back through the mirror.

It is to be understood that thin-film stacks may be used in a windowarrangement with a considerable degree of flexibility. To that end, FIG.9 illustrates a portion of a dual layer window arrangement, incross-section, generally indicated by the reference number 170, havingthe window arrangement between heating arrangement 52 and the treatmentobject (not shown) in the treatment chamber. Window arrangement 170includes a first window layer 172 and a second window layer 174. Apassage 176 may be defined between these window layers, as desired, andcould support a flowable material (not shown). Accordingly, windowarrangement 170 defines four window surfaces that are designated by thereference numbers 178 a-d. It is to be understood that at least anyselected one of these surfaces can support a thin-film stack. In thepresent example, a thin-film stack 180 is supported by window surface178 d.

Referring to FIG. 10 and again considering the subject of reflectivityresponse tuning, attention is directed to a section 190 of a chamberwall that is produced in accordance with the present invention. Wallsection 190 includes an outer structural wall member 192 formed, forexample, from aluminum. It is important to understand that layers can beapplied to wall member 172 in way which controls the infrared absorptionband edge so as to be able to “tune” the selective reflectivity. In thissense, “tuning” refers to an ability to shift the infrared absorptionband edge of a selective reflective wall configuration to either longeror shorter wavelengths.

The foregoing can be accomplished by a first appropriate layer 194 thatexhibits a selective reflective optical response when applied to thechamber surface, where it is desired to create a selective reflectivesurface. For purposes of the present example, it is assumed that theband edge produced by layer 194 is at a longer wavelength than isdesired. In accordance with the present invention, however, first layer194 can be over-coated with a second layer 196, using a material that isdifferent from that which first layer 194 is formed and having aninfrared absorption band edge at a shorter wavelength. By appropriatelyselecting a thickness for second layer 196, a shifted absorption bandedge is obtained resulting from the cooperation of the first and secondlayers. That is, an overall absorption band edge is provided having awavelength that is between the “intrinsic” wavelengths that arecontributed by the first and second layers, when consideredindividually. Accordingly, second layer 196 should be semitransparent inthe shorter wavelength region (below the desired crossover wavelength)and absorptive in the longer wavelength region (above the desiredcrossover wavelength). It should be appreciated that this implementationshould not be thought of in terms of being a thin-film effect, but as acombined response that arises from the bulk properties of the differentlayers. The combined response of the first two layers may be thought ofas that of a single layer for purposes of adding a third layer.

Having described the advantages of the present invention in detailabove, as well as a number of system embodiments, it is appropriate tonow provide more specific details with respect to predicted benefitsthat are attendant to its use in the context of a USJ (Ultra ShallowJunction) Spike Anneal process for a 300 mm semiconductor wafer.

FIG. 11 shows first and second temperature USJ anneal profiles, 200 and202, respectively, of temperature plotted against time. The results ofFIG. 11 were obtained using a set of equations in a computer model thatrepresent the wafer temperature response during the USJ “spike” process.The model was developed assuming that the wafer is heated at a constantrate when illuminated by heating arrangements both above and below thewafer (i.e., Tungsten-Halogen lamps). Also, it is assumed that thewafer-cooling rate is a function of the residual heat from the energysource, when the energy source is turned off (i.e. when electrical powerto the lamps is terminated) and that the lamps store residual energy intheir hot filaments and a smaller amount of energy is stored in andradiates from the quartz lamp envelopes. Heat loss is assumed throughradiation and convection from the wafer surface. The heat loss byradiation from the wafer surface, during the cooling period, is afunction of surface reflectivity of the chamber cavity. For thesepredictions, it is assumed that the lamp reflector plates represent themajority of relevant chamber surface area). Hence, the present exampleconsiders that selective reflectivity is applied only to the lampreflector surfaces.

Still referring to FIG. 11, first temperature profile 170 illustrates aprior art temperature profile, shown as a dashed line, and obtainedusing the aforedescribed model for a standard RTP system usingTungsten-halogen lamps with interior treatment chamber walls formed frompolished aluminum. Second temperature profile 202 considers an identicaltreatment chamber and wafer, except that the lamp reflector surfaces, inthis case only the surface behind the lamps with respect to the wafer,are coated with diffuse aluminum oxide. For first profile 200, a peakwidth ΔT₁, is shown for a temperature drop of 100 degrees C. having atime duration of approximately 1.93 seconds. For second profile 202,with the same temperature drop of 100 degrees C., however, thecorresponding peak width ΔT₂ is only approximately 1.71 seconds.Remarkably, an improvement of approximately 11.3% is demonstrated.Cool-down of the wafer is dramatically enhanced, with the cool-downperiod itself being shortened by approximately 15%.

Turning now to a discussion of the use of radiation pyrometry, in viewof the introductory discussion in the Background section of the presentapplication, a possible contradiction of requirements can arise when itis desired to provide a highly reflective surface for purposes ofincreasing the effective emissivity of a treatment object such as, forexample, a semiconductor wafer. In this regard, it may be desirable toprovide a chamber that is highly reflecting at the pyrometer wavelength.This desire may be at odds, however, with a desire to make the chamberhighly absorbing for most of the thermal radiation emitted by the wafer.

Referring to FIG. 12, the present invention resolves these competingdesires in a highly advantageous way through the use of a chamberinterior with a reflection spectrum that exhibits a high reflectivity atthe pyrometer wavelength, while the interior exhibits a low totalreflectivity for the thermal radiation spectrum of the wafer. To thatend, FIG. 12 illustrates a plot of an idealized spectral response 220 ofa selective reflective coating or material which provides theappropriate characteristics. Such a coating can be constructed in anysuitable way such as, for example, by design of a multi-layer thin filmstack. As mentioned above, such thin film stacks are producible by oneof ordinary skill in the art in view of a particular reflectancespectrum that is desired. Moreover, selection or fabrication of a bulkmaterial is contemplated that exhibits a reflectivity maximum at thepyrometer wavelength, but otherwise has a low total reflectivity. Anymaterial which provides a suitable spectral response, either currentlyavailable or yet to be developed, is contemplated for use herein.Response 220 includes a general drop 222 in reflectivity atapproximately 2 μm. A reflectivity peak 224 is centered at the pyrometerwavelength to reflect radiation in a narrow wavelength band that is, atleast approximately, centered on the pyrometer wavelength. As a note, itshould be appreciated that a spectral response without the presence ofpeak 224 represents the idealized reflectivity spectrum of a materialthat is suited for enhancing wafer cooling while still providing a highreflectivity for efficient lamp heating (see also FIG. 3).

The selection of the specific measurement wavelength used for pyrometrycan be at least partly based on the availability of a suitable materialor thin-film stack. While the term “pyrometer wavelength” is used hereinas if the pyrometer is responsive at only one wavelength, it is to beunderstood this term refers to the center of a relatively narrowwavelength band over which the pyrometer is responsive.

Referring to FIG. 13 in conjunction with FIG. 12, the formerdiagrammatically illustrates a system 240 having a treatment chamber 242with upper and lower lamp arrays 52 a and 52 b, respectively, positionedtherein for illuminating opposing surfaces of a treatment object 64 suchas, for example, semiconductor wafer 64. A pyrometer or a set ofpyrometer light collection optics 250 is provided with a view of thewafer through the chamber wall and between adjacent ones of the lampsfor sensing the wafer temperature. While only one pyrometer arrangementis illustrated in the present example, for purposes of simplicity, anysuitable number may be employed viewing either or both sides of thewafer, as will be further described. Further, a selective reflectivityinterior 252 has been provided in chamber 242 which implements thespectral response that is illustrated by FIG. 12. In this way,reflectance of the chamber interior is high at the pyrometer wavelengthwhile providing the advantages described above with respect to waferheating and cooling characteristics.

In view of FIG. 12, the present invention has provided a highlyadvantageous and heretofore unseen customized spectral response orspectral response system which is tailored or customized to waferheating, wafer cooling and enhanced temperature measurement. It iscontemplated that additional factors relevant to chamber performance maybe accounted for in this overall spectral response system, resulting inheretofore unavailable benefits. For example, as will be furtherdescribed, the chamber response may be customized to attenuate straylight which might enter the pyrometer(s). It is to be understood thatthe chamber arrangement of FIG. 13, like all other chamber arrangementsdescribed herein, may be customized in any suitable manner, as will befurther described.

The present invention recognizes a general principle wherein the chamberreflection spectrum is designed to simultaneously optimize the heatingand/or cooling performance in conjunction with the pyrometer accuracy.In this regard, there may also be advantages in some pyrometry schemeswith respect to making the chamber (or parts of the chamber) highlyabsorbing at the pyrometer wavelength. As one example, the distributionof stray light from the heating arrangement lamps can be controlledwithin the chamber such that the stray light has minimal impact onpyrometer readings. In order to achieve this, a low reflectivity at thepyrometer wavelength may be provided, either across the whole of thechamber, or limited to portions of the chamber walls that tend to guidelight from the heating lamps into optical paths that lead into thepyrometer optics. This recognition, in and by itself, to design thechamber walls in a way which attenuates those stray light paths, may beproven as a powerful concept for future chamber design that stands onits own, aside from other highly advantageous recognitions brought tolight by the present invention such as, for example, enhanced cooling.Control of stray light is of concern at least for the reason that thereis an ongoing concern with wafer temperature measurement, which isusually affected by reflector design. Accordingly, a spectrallyselective coating that allows separate, customized optimization ofheating/cooling performance (for example, heating rate and coolingrate), and uniformity, as well as pyrometer design, is considered toprovide sweeping improvements over the prior art, standing on its ownmerits. At the same time, this recognition is considered to provideremarkable improvements in combination with other highly advantageousconcepts taught herein.

Attention is now directed to FIG. 14 which diagrammatically illustratesanother possible solution for optimizing pyrometer response in a systemembodiment that is generally indicated by the reference number 260. Inparticular, a chamber wall surface arrangement 262 provides for highreflectivity only locally in a region 264 around the pyrometer apertureitself. The chamber may otherwise provide a selective reflectiveinterior 266, indicated by a heavy line. In this way, a majority of theproperties of the chamber wall can be preserved, in particular, withrespect to providing enhanced wafer cooling. It is noted that interior266 may be optimized for the pyrometer by having a low reflectivity atthe pyrometer wavelength for purposes of suppressing stray light such asis conceptually understood with reference to FIG. 15, yet to bedescribed. In order to avoid excessive cooling non-uniformity in thewafer, however, region 264, with high reflectivity, should be quitesmall and/or the wafer should be rotated, such that any non-uniformityproduced by this region is swept across the wafer surface, so as toazimuthally average out any local temperature non-uniformity arisingfrom the chamber non-uniformity. One criterion, well known to those ofskill in the art. for insuring that region 264 is sufficiently large,around the pyrometer aperture for significant emissivity enhancement, isbased on the distance between the pyrometry aperture and the wafer, aswell as the angular acceptance range of the pyrometer optics. One morestraightforward approach suggests that the region of high reflectivityshould have a radius of at least 0.25 times the distance between theaperture and the wafer. This conflicts with the uniformity requirementof keeping the region small, thus emphasizing the benefit of aspectrally selective approach, as taught by the present invention. In analternative implementation, region 264 can be highly absorbing, ratherthan highly reflecting. Such an implementation can be useful for apyrometer wherein a different emissivity correction scheme is utilized.Such a high absorption implementation may then be employed forattenuating stray light incident on the absorbing surface, especiallywith respect, but not limited to stray light originating from the lampsnear the pyrometer input optics. FIG. 15 is a plot of an idealizedspectral response 270 of selective reflective interior 266 of FIG. 14,assuming a pyrometer wavelength of 1 μm. Response 270 includes generaldrop 222 in reflectivity, as well as a reflectivity trough 272 at awavelength of 1 μm for use in suppression of stray radiation in thepyrometer band centered at 1 μm. Comparison of FIG. 15 with FIG. 12 isinstructive with respect to understanding that the location of pyrometerresponse band is selectable. Moreover, depending upon the immediateobjectives, it may be desirable to suppress the pyrometer wavelength orto reflect it. In some embodiments, one portion of the of the chambermay selectively reflect the pyrometer wavelength while another portionof the chamber may selectively absorb the pyrometer wavelength. Forexample, region 264 of FIG. 14 may be configured to selectively reflectonly the pyrometer wavelength while region 266 responds according toFIG. 15. In an alternative implementation, the spectral response of FIG.15 can be used for interior 252 of the system arrangement of FIG. 13,for example, in the case where the pyrometer is more disturbed by straylight than by emissivity issues. Moreover, the spectral response of FIG.15 can also be useful in system 260 of FIG. 14, wherein it is desiredthat region 264 attenuate stray light when emissivity has otherwise beenaddressed. With regard to all of these various examples, it is importantto realize that any number of alternative, customized responses may beformulated, based on design concerns which can arise in a particularsetting. For example, in one setting it may be desirable for a selectedregion to be absorbing or selectively absorbing while in another settingit may be desirable for that very same region to be reflecting orselectively reflecting. In view of the teachings herein, it is submittedthat the present invention provides a highly flexible set of designconcepts which may be used to overcome a wide array of design objectivesfaced by those having ordinary skill in the art for purposes ofcustomizing chamber response.

FIG. 16 diagrammatically illustrates a system 280 having single-sidedwafer heating using heating arrangement 52 within a chamber 282. Achamber interior 284 is treated uniformly to provide selectivereflection throughout the chamber. Pyrometer 250 or its optics arearranged to view a lower surface of wafer 64. The reflection spectrum ofinterior 284 may be optimized for pyrometer 250. Again, depending on thepyrometer details, there may be benefits to having either a high or alow reflectivity at the pyrometer wavelength.

FIG. 17 diagrammatically illustrates a system 290 having single-sidedwafer heating using heating arrangement 52 within a chamber 292optimized for pyrometry. One portion 294 of the chamber around thepyrometer is selectively reflective to optimize pyrometer performance.Another portion 296 of the chamber interior, indicated by a thick, solidline, is spaced away from the pyrometer optics so that its reflectionspectrum is not necessarily optimized for the pyrometer. However,portion 296 may nonetheless be optimized, for example, to have a lowreflectivity at the pyrometer wavelength for better suppression of straylight (see FIG. 15). It is noted that portion 294, surrounding thepyrometer may be configured in any suitable manner that is differentfrom portion 296, in view of the design circumstances encountered, anumber of possible ones of which are outlined above.

FIG. 18 diagrammatically illustrates a system 300 having single-sidedwafer heating using heating arrangement 52 within a chamber 302. In thisexample, a selective reflector coating 304, indicated using a thick,solid line, is designed to optimize pyrometer performance for thesingle-sided heating chamber. In particular, the selective reflectivityis not excluded from the region around the pyrometer optics, so itsreflection spectrum may be optimized for the pyrometer, for example, bymaintaining a high reflectivity at the pyrometer wavelength. In thissituation, the coating could be absorbing at all wavelengths apart fromthe pyrometer wavelength, as will be illustrated. It is noted that aportion of the bottom surface of the chamber which confronts the waferhas been treated with coating 304 in the present example. As a result ofthe presence of coating 304, it should be appreciated that a uniformprocessing result is likely. Remaining portions 306 of the chamberinterior, indicated using a double line, may be treated for purposes ofefficiently reflecting lamp radiation. Alternatively, coating 304 mayconfigured for stray light suppression depending, for example, onpyrometry concerns with respect thereto. Of course, selectivereflectivity may be employed, consistent with the descriptions above. Inone implementation, portions 306 of the chamber may be treated withselective reflectivity to enhance wafer heating/cooling performance. Inanother implementation, portions 306 may be treated to absorb thepyrometer wavelength as is illustrated by reflectivity trough 272 ofFIG. 15. Moreover, these implementations may be combined such thatportions 306 respond in a manner that is consistent with FIG. 15.

Attention is now directed to FIG. 19 in conjunction with FIG. 18. Theformer is a plot of an idealized spectral response 310 of selectivereflective coating 304, assuming a pyrometer wavelength of 2.5 μm.Response 310 includes a reflectivity peak 312 in a narrow wavelengthband centered at approximately 2.5 μm such that all other wavelengthsare attenuated in relation to the pyrometer wavelength. This approach isconsidered to be useful in a single-sided heating system for theenhancement of effective emissivity at that wavelength. The coating canbe limited to the reflector that is beneath the wafer. Since there areno lamps located below the wafer, the short-wavelength reflectivity neednot be high.

FIG. 20 diagrammatically illustrates a system 320 having single-sidedwafer heating using heating arrangement 52 within a chamber 322. Aregion 326 includes a portion of the chamber bottom, shown as a heavyline, which is exclusive of a region 328 around the pyrometer optics.Region 328 is treated, for example, using a coating, so the reflectionspectrum of region 326 is not required to be optimized for thepyrometer. Region 328, however, is configured for high reflectivity inthe pyrometer band. With respect to pyrometry performance, region 326can be optimized, for example, to have a low reflectivity at thepyrometer wavelength for better suppression of stray light, such as isillustrated by FIG. 15. In one alternative embodiment, region 326 can bea broadband absorber for purposes of pyrometry improvement and enhancedwafer cooling.

FIG. 21 is a diagrammatic plan view taken from above wafer 64, which isshown as transparent for illustrative purposes. Wafer 64 is within achamber 330, produced according to the present invention, havingsingle-side or dual-side heating. Wafer 64 is rotated, as indicated byan arrow 332, past the field-of-view of multiple pyrometers 250 a-c (oroptics thereof) at various radii 334 a-c from the center of the wafer. Aselective reflector, or absorber coating 336 is applied on the chamberbottom and can be excluded from regions 338 a-c, respectively, aroundeach pyrometer in order to avoid performance compromises in thepyrometry, consistent with the foregoing descriptions. Although each ofthe aforedescribed physical embodiments have been illustrated withvarious components having particular respective orientations, it shouldbe understood that the present invention may take on a variety ofspecific configurations with the various components being located in awide variety of positions and mutual orientations. Furthermore, themethods described herein may be modified in an unlimited number of ways,for example, by reordering, modifying and recombining the various steps.Accordingly, it should be apparent that the arrangements and associatedmethods disclosed herein may be provided in a variety of differentconfigurations and modified in an unlimited number of different ways,and that the present invention may be embodied in many other specificforms without departing from the spirit or scope of the invention.Therefore, the present examples and methods are to be considered asillustrative and not restrictive, and the invention is not to be limitedto the details given herein, but may be modified at least within thescope of the appended claims.

1. A system for processing a treatment object having a given emissionspectrum at a treatment object temperature which causes the treatmentobject to produce a treatment object radiated energy, said systemcomprising: a heating arrangement for heating the treatment object usinga heating arrangement radiated energy having a heat source emissionspectrum at a heat source operating temperature which heat sourceemission spectrum is different from said given emission spectrum of thetreatment object; a sensor arrangement for sensing the treatment objectradiated energy at a sensing wavelength; and a chamber arrangement forexposing said treatment object to a portion of the heating arrangementradiated energy while supporting said treatment object within atreatment chamber, at least one portion of said chamber arrangementconfigured for simultaneously (i) responding in a first way to amajority of the heating arrangement radiated energy that is incidentthereon, (ii) responding in a second way to a majority of the treatmentobject radiated energy that is incident thereon and (iii) responding ina third way at the sensing wavelength.
 2. The system of claim 1 whereinsaid portion of the chamber arrangement is configured for one ofreflecting or absorbing said majority of said sensing wavelength that isincident thereon.
 3. The system of claim 2 wherein said portion of thechamber arrangement is configured to respond in said first way byreflecting said majority of the heat source radiated energy and torespond in said second way by absorbing said majority of the treatmentobject radiated energy.
 4. The system of claim 1 wherein said portion ofthe chamber arrangement is configured to reflect said majority of saidsensing wavelength that is incident thereon.
 5. The system of claim 4wherein said portion of the chamber arrangement is configured to respondin said first way by reflecting said majority of the heat sourceradiated energy and to respond in said second way by absorbing saidmajority of the treatment object radiated energy.
 6. In a system forprocessing a treatment object having a given emission spectrum at atreatment object temperature which causes the treatment object toproduce a treatment object radiated energy, a method comprising: heatingthe treatment object using a heating arrangement radiated energy havinga heat source emission spectrum at a heat source operating temperaturewhich heat source emission spectrum is different from said givenemission spectrum of the treatment object; sensing the treatment objectradiated energy at a sensing wavelength; and configuring a chamberarrangement for exposing said treatment object to a portion of theheating arrangement radiated energy while supporting said treatmentobject within a treatment chamber, at least one portion of said chamberarrangement configured for simultaneously (i) responding in a first wayto a majority of the heating arrangement radiated energy that isincident thereon, (ii) responding in a second way to a majority of thetreatment object radiated energy that is incident thereon and (iii)responding in a third way at the sensing wavelength.
 7. The method ofclaim 6 wherein said portion of the chamber arrangement is configuredfor one of reflecting or absorbing said majority of said sensingwavelength that is incident thereon.
 8. The method of claim 7 whereinsaid portion of the chamber arrangement is configured to respond in saidfirst way by reflecting said majority of the heat source radiated energyand to respond in said second way by absorbing said majority of thetreatment object radiated energy.
 9. The method of claim 6 wherein saidportion of the chamber arrangement is configured to reflect saidmajority of said sensing wavelength that is incident thereon.
 10. Themethod of claim 9 wherein said portion of the chamber arrangement isconfigured to respond in said first way by reflecting said majority ofthe heat source radiated energy and to respond in said second way byabsorbing said majority of the treatment object radiated energy.
 11. Asystem for processing a treatment object having a given emissionspectrum at a treatment object temperature which causes the treatmentobject to produce a treatment object radiated energy, said systemcomprising: a heating arrangement for heating the treatment object usinga heating arrangement radiated energy having a heat source emissionspectrum at a heat source operating temperature which heat sourceemission spectrum is different from said given emission spectrum of thetreatment object; a sensor for sensing the treatment object radiatedenergy emitted by said treatment object at a sensing wavelength; and achamber arrangement for exposing said treatment object to the heatingarrangement radiated energy while supporting said treatment objectwithin a treatment chamber, at least a first portion of said chamberarrangement configured for reflecting a majority of the sensingwavelength that is incident thereon, and a second, different portion ofthe chamber arrangement configured for selectively absorbing a majorityof the sensing wavelength that is incident thereon.
 12. The system ofclaim 11 wherein said first portion is configured for selectivelyreflecting said majority of the sensing wavelength incident thereon. 13.The system of claim 11 wherein said treatment object defines first andsecond opposing major surfaces and said heating arrangement confrontsand directly heats only the first major surface of the treatment objectand wherein said first and second portions of the chamber arrangementmake up different parts of a chamber surface which confront said heatingarrangement and the second major surface of the treatment object. 14.The system of claim 13 wherein said sensor senses from said firstportion of the chamber arrangement.
 15. The system of claim 14 whereinsaid sensor senses, at least approximately, from a centered position ofsaid first portion of the chamber arrangement.
 16. The system of claim14 wherein said sensor directly confronts the second major surface ofthe treatment object.
 17. In a system for processing a treatment objecthaving a given emission spectrum at a treatment object temperature whichcauses the treatment object to produce a treatment object radiatedenergy, a method comprising: heating the treatment object using aheating arrangement producing a heating arrangement radiated energyhaving a heat source emission spectrum at a heat source operatingtemperature which heat source emission spectrum is different from saidgiven emission spectrum of the treatment object; providing a sensor forsensing the treatment object radiated energy emitted by said treatmentobject at a sensing wavelength; and configuring a chamber arrangementfor exposing said treatment object to the heating arrangement radiatedenergy while supporting said treatment object within a treatmentchamber, at least a first portion of said chamber arrangement configuredfor reflecting a majority of the sensing wavelength that is incidentthereon, and at a second, different portion of the chamber arrangementconfigured for selectively absorbing a majority of the sensingwavelength that is incident thereon.
 18. The method of claim 17 whereinsaid first portion is configured for selectively reflecting saidmajority of the sensing wavelength incident thereon.
 19. The method ofclaim 17 wherein said treatment object is formed to define first andsecond opposing major surfaces and said heating arrangement confrontsand directly heats only the first major surface of the treatment objectand wherein said first and second portions of the chamber arrangementare configured to make up different parts of a chamber surface whichconfront said heating arrangement and the second major surface of thetreatment object.
 20. The method of claim 19 including arranging saidsensor to sense from said first portion of the chamber arrangement. 21.The method of claim 20 wherein said sensor is arranged for sensing, atleast approximately, from a centered position of said first portion ofthe chamber arrangement.
 22. The method of claim 20 wherein said sensoris arranged to directly confront the second major surface of thetreatment object.